When a dental pulp is deeply infected being provoked by dental caries, a treatment comprising pulling our the pulp (extirpation of the pulp) under anesthesia and filling the cavity (hereinafter referred to as pulp cavity) utlimately with cement to preserve and function the natural tooth within the oral cavity is required. In the treatment, a dental root canal-treating appliance for cleaning pulp cavity and/or for application of medicine is used.
The first stage of the treatment of root canal aims at killing innumerable bacteria on the wall surfaces of the root canal and in the dentine around the root canal wall and curing inflammation in periapical tissues. For this purpose, the dentist grates out the enamel layer 16 of the crown 15 of the diseased tooth (in the example shown in the attached illustration, an anterior tooth) (FIG. 1) and the wall of pulp chamber 17, then pulls out the dental pulp (nerve fibre and others) and grates out the root canal wall with an appliance, thus enlarges and forms the root canal 19 as shown in FIG. 2, leaving the apical foramen (hereinafter referred to as root canal formation). And thereafter an aqueous hydrogen peroxide, a solution of sodium hypochlorite, and water is poured into said root canal 19, or further thereafter, a disinfectant essentially comprising phenol, cresol, formaline etc. is applied thereto and the process is observed for several days. Thereby the infected root canal where bleeding, pus, serous and the like 21 (FIG. 3) were observed at first at the bottom of the root canal is made to gain momentum for curing. And subsequently, after confirming through culture test that the inside of the root canal is brought to aseptic state, zinc white-eugenol cement (as a favorable example, there is "CANALS", the trade mark of a product of Showa Yakuhin Kako K.K.) is filled and hardened, then in the pulp chamber 17, i.e. the root canal 19, zinc phosphate cement (as a favorable example, there is "Duraphos-S", the trade mark of a product of Showa Yakuhin Kako K.K.) is filled and hardened, and ultimately it is covered with gold crown (prothesis) to complete the treatment. And in such treating procedure in the prior art, for cleaning the inside of the root canal or for application of medicine, a cotton- or Japanese paper-work such as "broach cotton" formed by winding up a piece of cotton on to a wire, or "paper point" made by twisting a piece of Japanese paper has conventionally been used.
However, said "broach cotton" which the dentist produces by winding cotton onto a wire with his finger tips requires a skill to form it, and the amount of cotton cannot be definite, and if the cotton is used too much, it makes it difficult to insert it into the root canal, and if it is too small on the contrary, it not only cannot absorb the filth thoroughly, but since it is winded with finger tips, besmearing with bacteria cannot be avoided, and further it has the defect that cotton fibers remain in the canal. Said "paper point", on the other hand, has not so much defect as said "broach cotton", but it lacks firmness, and particularly when wetted, it often cannot reach the point around the apical foramen, and further, it takes a long time for absorbing not only pus but even water, and for absorbing blood, pus, serous or water from one root canal, it requires to use about 10 pieces of broach cotton or paper points in average.
On the other hand, as shown in FIG. 5 of the accompanying drawings, Japanese Utility Model Public Disclosure No. 93298/1979 proposes a root canal-treating appliance 10a as the product that improves the aforementioned defects, where one or both ends of a axially-arranged fibrous thin rod are formed into a conical shape and sterilized. The major improvement of this improved product lies in that the fibrous material is even up to the axial direction, but when a fibrous material even up to the axial direction is merely formed into the needlelike taper 10a and used for the treatment, the fiber ends, i.e. fine splits are projecting which not only impart extra irritation to the periapical tissue but also injure even the periodontal membrane, and quite naturally push out bacteria outside the apical foramen and may invite aggravation of the disease. Since the wall surface of the root canal formation 19, i.e. root canal wall 20, is composed of dentine but has tubles, it is apt to get injured by the needle-like taper having fine splits. Furthermore, because all the peripheral surface of the taper 10a having the length 20-30 mm has to be ground with a grinder or the like, the surface of the appliance itself lacks in smoothness, and moreover, the ground powder of the fibrous material is apt to attach and may remain within the root canal as foreign matters. Furthermore, with the structure of such shape, it is difficult to gain a definite drift of the liquid absorption within the root canal, and due to the irregular absorption from the surrounding surfaces, absorption from the tip end tends to be disturbed. And because of these defects, further improvements have been called for the appliance to be used for depuration and medicine-application for the inside of the root canal including the apical foramen 13.